A meeting between Aer Lingus management and unions to discuss the €780 million pension fund deficit broke up in disarray after what were described as "robust" and "personalised" exchanges between negotiators.
Sources on both sides confirmed that the management negotiators walked out of the meeting after heated exchanges with a union representative.
An airline spokesperson confirmed that management attended a meeting today with the ICTU and the company's unions to discuss the pensions issue.
He said a number of matters unrelated to the pension issue were introduced in a manner that was unacceptable to Aer Lingus.
It is understood that those matters involved disciplinary proceedings concerning a staff member.
The spokesperson said the atmosphere at today's meeting was therefore "not conducive to appropriately discussing the pension matter".
He said they were keen to progress the resolution of the pension matter and would write to ICTU to comprehensively address the pension matters they raised recently in their correspondence.
The union delegation is now attending a meeting with the Dublin Airport Authority, which is also covered by the same pension scheme.
The scheme has a deficit estimated at €780 million and management and unions are in dispute over how much the companies should contribute to plug the shortfall.
Negotiations have been continuing for some years amid fears that the scheme's members who have not yet retired will lose a significant portion of the pensions they are expecting.
A funding proposal to address the deficit was rejected by the Pensions Board during the summer.
The pension deficit has been viewed as a serious obstacle to the Government's plan to sell its 25% stake in Aer Lingus, as well as to the company's attempts to build alliances aimed at growing the airline.